Wind surfing apparatus are generally formed with a hull to which a mast and sail are pivotally mounted to project upward from the hull during sailing. The hull is usually in the form of a sail board having a somewhat flat top surface upon which the user stands in counterbalanced relationship to the sail, and a lower surface which is hydrodynamically formed to move through the water under sail power. At appropriate speeds, the hull is capable of hydroplaning as is well known.
A removable daggerboard projects downward from the hull, rearwardly of the mast, to counterbalance the wind force acting upon the sail when the wind is from the side or the front of the board; the conventional daggerboard also provides a small degree of rotational stability about the long axis of the board.
The daggerboard is constructed and arranged to be removably mounted on the hull in a manner enabling rapid mounting and de-mounting while also being rigidly secured in use. This is often achieved by providing a through slot in the central portion of the hull that communicates with top and bottom surfaces thereof. The lower end of the daggerboard is inserted into the open top of the slot and slides downwardly until restrained by a pair of pivot protrusions which are received and cradled within a pair of shallow depressions formed in the top surface of the board in communication with the slot. These pivot protrusions define a transverse pivot axis located perpendicular to the longitudinal axis of the hull.
One of problems associated with the conventional daggerboard described hereinabove is that the lower end moving through the water is hydrodynamically shaped and somewhat light in weight and therefore cannot easily resist the tendency of the board to be unstable by rolling along its longitudinal axis or to actually flip over. The tendency of the hull to be unstable is a particular problem for novice board sailors and frequently is a sufficient source of frustration for the novice sailor so as to discourage board sailing instruction. The problem of tipping or flipping also plagues intermediate level sailors particularly when learning to do beach starts, water starts and jibes.
It is accordingly an object of the present invention to resist the tendency of wind surfing apparatus to flip.
Another object of the invention is to improve rotational stability of wind surfing apparatus.
Since the aforementioned daggerboard is removable and mounted to the hull by simple downward placement through the open vertical slot, there is a tendency for the lower submerged end of the daggerboard to pivot rearwardly during sailing which lessens its ability to counteract the wind force acting upon the sail, thereby increasing the tendency of the board to flip especially at higher speeds. To prevent this problem, the sailor must constantly or at periodic intervals apply pressure to the upper portion of the daggerboard to ensure that the daggerboard remains in its lowermost position during sailing.
In contrast to the problem identified hereinabove, advanced sailors may desire to pivot the daggerboard into different orientations relative to the hull in order to practice advanced maneuvers or to accomplish beach starts under conditions of shallow depth and gradual bottom slopes where considerable horizontal distances must be traversed before the daggerboard can be pivoted into its lowermost and deepest position.
A further object is to positively control the orientation of the removable daggerboard relative to the hull.
Another object is to prevent pivotal movement of the daggerboard during sailing by positively maintaining the daggerboard at a fixed orientation with respect to the hull irrespective of sail speeds.